Electromagnetic relay



July 18, 1961 J. s. ZIMMER ELECTROMAGNETIC RELAY 3 SheetsSheet 1 FiledJan. 26, 1960 INVENTOR JOHN s. ZIMMER, MW? 0mm ATTORNEY.

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1961 J- 5. ZIMMER 2,993,103

ELECTROMAGNETIC RELAY Filed Jan. 26, 1960 s Sheets-Sheet 2 NORMALLY OPENTERMINAL 2 -24 SWITCH N0-2 I I NORMA NORMALLY I CLOS CLOSED Z TERM|NAL4TERMINAL I0 NORMALLY I CLOSED NORMALLY TERMINAL 2 OPEN 2 SWITCH N0 4TERMINALS l6 IO lo u I i I flWf i I i SWITCH No.2v- 5 NORMALLY CLOSED l6NORMALLY TERMINAL3 c SED NORMALLY/ 7 TER CLOSED g4 TERMINALS |o SWITCHNo.6 I 24/ N MALLY OPEN I NORMA Y OPEN RMINALG TER AL s V INVENTORZ JOHNs. ZIMMER,

W3 ATTORNEY.

July 18, 1961 J. s. ZIMMER ELECTROMAGNETIC RELAY Filed Jan. 26, 1960 3Sheets-Sheet 3 SWITCHING swncnms TERMINAL l TERMINAL 2 con. TERMINAL@NORMALLY CLOSED TERMINAL \fisia'iwxfiaaaai NORMALLY OPEN TERMINALINVENTOR I JOHN S. ZIMMER nited States Patent O 7 2,993,103ELECTROMAGNETIC RELAY John S. Zrrnmer, Waynesboro, Va., assignor toGeneral Electric Company, a corporation of New York Filed Jan. 26, 1960,Ser. No. 4,703 4 Claims. (Cl. 200-87) The invention relates to anelectromagnetic relay, and particularly to a compact assembly comprisinga plurality of individual electromagnetic switches.

An object of the invention is to provide an improved relay assembly of aplurality of electromagnetic switches.

Another object of the invention is to provide an improved and novelrelay assembly comprising a plurality of electromagnetic switches, theassembly being relatively small and compact.

Another object of the invention is to provide an improved relay assemblycomprising a plurality of individual electromagnetic switches, all ofthe individual switches being operated by a single common winding.

The invention is an improwement and utilization of the inventiondescribed and disclosed in the copending patent application filed in thename of I S. Zimmer on January 21, 1959, Serial No. 788,197. Theinvention contemplates the use of a switch such as described and shownin this copending application, but is not to be considered limited tosuch a switch. As will be apparent to persons skilled in the art, theinvention can be used with a number of different embodiments. Briefly,in accordance with the invention, a number of basic or individual switchunits or switches are assembled together with an insulating strippositioned between each of the switches. Brackets, preferably having anL-shaped configuration, are fastened to each of the ends of the switchcores for two purposes. The first is to provide a convenient terminalpoint for connecting certain of the switch elements to externalcircuitry. The second is to provide a relatively low reluctance path forthe magnetic circuits of the individual switches. A single coil orwinding is positioned around all of the switch elements. The coil, theswitches, and the L-shaped brackets are surrounded by a suitableinsulating material. The insulating material, in turn, is surrounded bya suitable cover of magnetic material which is separated from the L-shaped brackets by an amount equal to the thickness of the insulatingmaterial. Thus, the paths for the magnetic circuits of each switchcomprise a low reluctance magnetic material and a small air gap equal tothe thickness of the insulation. This provides an extremely desirablearrangement inasmuch as the low reluctance magnetic paths insure goodpickup operation when the relay coil is energized, and the air gapprovides or insures satisfactory dropout of the relay when the coil isrte-energized.

The invention will be better understood from the fol lowing descriptiontaken in connection with the accompanying drawing and its scope will bepointed out in the claims. In the drawing:

FIGURE '1 shows a longitudinal cross-sectional view of one embodiment ofa relay assembly in accordance with the invention, the view of FIGURE 1being taken along the lines 1- 1 of FIGURES 2 and 3 and further showinga portion broken away to illustrate one example of an individual switchconstruction which may be used in the assembly;

FIGURE 2 shows a transverse cross-sectional view of the relay assemblytaken along the lines 2--2 of FIG- URE l and also shows a portion brokenaway for illustrating one example of an individual switch constructionwhich may be used in the assembly;

FIGURE 3 shows an elevation or side view of the as- Patented July 18,1961 sembly of FIGURE 1 as viewed from the right of FIG URE l; and

FIGURE 4 shows a transverse cross-sectional view of another embodimentof the relay assembly.

In the figures, the same reference numerals are used to refer to thesame elements. In FIGURES 1, 2, and 3, a relay assembly comprising sixindividual, single pole, double throw switches is shown. Again, it isemphasized that the invention need not be limited to an arrangementcomprising six individual switches as shown in FIG- URES l, 2, and 3 orneed not be limited to an arrangement comprising three individualswitches as shown in FIGURE 4. The arrangements shown are examples only,and in accordance with the spirit and scope of the invention, may beextended to any number (including two or more) of switches assembled inaccordance with the invention.

With reference to FIGURES 1, 2, and 3, there is shown a relay assemblycomprising six individual switches arranged as shown. As will beexplained in greater detail, each of the switches may be housed in acylindrical metallic tube 10 of nonmagnetic material such as nonmagneticstainless steel. The cylindrical tubes 10, each containing itsrespective switch, are arranged to form three rows of two tubes each,with the tubes coextensive, and with their longitudinal axes parallel.Each of the cylindrical tubes 10 is electrically insulated from theadjacent cylindrical tubes 10 by means of insulating strips 12 formed ofsome electrically insulated material such as a plastic. The insulatingstrips 12 extend beyond the cylindrical tubes 10 as shown in FIGURE 1.As will also be explained hereinafter, each of the individual switchesmay be a hermetically sealed unit. Projecting from the ends of theindividual switches are core extensions 14, 16, which :form a part ofthe switch magnetic circuit. These core extensions 14, 16 are generallycylindrically shaped and formed of a magnetic material. Surrounding andproviding support for the individual switches and the insulating strips12 is a spool-shaped coil form 18 made of an electrically insulatingmaterial such as plastic. The coil form 18 has the configuration orshape as to surround the individual switches as closely as possible andhold them in the desired position. A coil 20 is wound on the coil form18 and its ends are brought out on coil terminals 22. As shown in FIGURE1, the coil form 18 and coil 20 leave a portion of the core extensions14, 16, uncovered to provide clearance for L-shaped brackets 24. Each ofthe outer ends of the core extensions 14, 16 have a portion which isground or machined to provide a fiat surface on which one L-shapedbracket 24 is fastened. The fiat surface portion of the core extensions14, '16 are oriented so that the L-shaped brackets 24 provide an outlineor framework on which an assembly cover 26 may be mounted. The L-shapedbrackets 24 are made of a magnetic material, and may be fastened totheir respective core extensions 14, 16 by any suitable means, such aswelding. Surrounding the L-shaped brackets and the coil form 18 and coil20 is the assembly cover 26 which is made of magnetic material and whichpreferably has an insulating strip 28 located around its entire innersurface. The insulating strip 28 may be made of any suitable electricalinsulating material such as a plastic film or coating. The assemblycover 26 is positioned over or around the coil form 18, the coil 20, andthe ends of the L-shaped brackets 24. The cover 26 is preferablydimensioned to provide a fairly snug fit and at the same time not scaror break the insulating strip 28.

An individual terminal is connected to each of the L-shaped brackets 24to each of the cylindrical tubes 10 to provide electrical connections tothe switch elements as will be explained. With the arrangement justdescribed assembled within the assembly cover 26, a suitable thermallysetting potting compound of electrically insulating material such asepoxy filled resin may be poured into the ends of the entire assembly tofirmly support and insulate the various connections and elements in theproper manner.

Before the operation of the novel and improved relay assembly isdiscussed, the construction of one of the individual switches will beexplained. In FIGURE 1, a longitudinal cross-sectional view of switchNo. 3 is. shown, this view of switch No. 3 being taken along the dashedline in FIGURE 2 which passes through the center of switch No. 3. Atransverse cross-sectional view of switch No. 4 is shown in FIGURE 2,this cross-sectional view being taken along the dashed line in FIGURE 1which passes through the center of switch No. 3. As already mentioned,each of the individual switches comprises cylindrical core extensions14, 16 formed of a magnetic material. The core extensions 14, 16 arerespective extensions of first and second core elements 40, 42 which arepreferably, but not necessarily, integral and formed from the samematerial as their respective core extensions 14, 16. The core elements40, 42, which are also cylindrical, are axially aligned and areseparated by an air gap 44 which, as shown in FIGURE 1, may be generallydescribed as X-shaped and which is formed by the free or inner endsurfaces of the core elements 40, 42. An armature 46 is formed from thematerial of the core elements 40, 42, and has a shape which correspondsto or substantially fits in a portion of the air gap 44. This process isfully discussed in the copending application mentioned above. Thearmature 46 is fastened to a spring 48 which in turn is fastened to aflat portion of the first core element 40 by any suitable means such aswelding. The spring 48 is preferably made of a fiat elongated strip ofresilient material such as an alloy of silver, nickel, and magnesium,and is bent or shaped so that it rests substantially in the positionshown in FIGURE 1. The spring 48 carries a spring contact 50 preferablyformed of a high conductivity metal that is silver plated, the springcarried contact 50 being on the opposite side of the spring 48 from thearmature 46. The spring carried contact 50 normally (i.e., when theswitch is released) engages a contact bar 52 which is also preferablyformed of a high conductivity metal that is silver plated. The contactbar 52 has an extension which is bent to provide a backstop 54 for thefree end 56 of the spring 48. The backstop 54 helps to reduce bouncingor oscillation of the spring 48 when the switch is released or droppedout to its normal position. The free end 56 of the spring 48 ispositioned in the vicinity of the second core element 42 but is normallyseparated therefrom. When the switch is energized (i.e., pulled up fromits normal position), the free end 56 of the spring 48 engages a contact58 which is preferably formed of a high conductivity metal that issilver plated, and which is fastened to a flat portion of the secondcore element 42. Since the free end 56 of the spring 48 provides anelectrical circuit to the cont-act 58 on the second core element 42, andsince the free end 56 may flex or whip when the switch is released ordropped out so that the free end 56 engages the backstop 54 before thespring carried contact 50 engages the contact bar 52, the entire spring48 or at least the free end 56 portion may preferably be plated oralloyed with a suitable high conductivity metal such as silver,

The contact bar 52 and its backstop 54 are supported by an inner tube60. The inner tube 60 is formed from a suitable piece of cylindrical,nonmagnetic material such as stainless steel so that it has twocylindrical end supports 62, 64 which are joined by two longitudinallyrunning strips 66. On the lower side and between the two strips 66, asemicylindrical support 68 is provided. This support 68 carries thecontact bar 52 and its backstop 54. The contact bar 52 is preferablyfastened to the support 2,998,103 j r c f 68 before the switch isassembled. The inner tube 60 is supported in an electrically insulatedrelation between the core extensions .14, 16 of the respective coreelements 40, 42 by electrically insulating cylindrical heads 7 0 whichsurround the core extensions 14, 16 and bear against the shouldersformed by the core elements 40, 42. The cylindrical beads 70 may berigidly fastened to the core extensions 14, 16 by any suitable means.Glass beads are preferred as they can be fused to the core extensions14, 16 to provide a hermetic seal. When in position, the inner tube 60is outside the core elements 40, 42, part of the core extensions 14, 16and the cylindrical beads '70. The inner tube 60 is supported by andrigidly fastened to the beads 70 at its respective end supports 62, 64.The metallic cylindrical tube 10 of nonmagnetic material is placedaround the inner tube 60 to completely enclose and surround the switchelements. The cylindrical tube 10 may be fastened to the inner tube 60around the entire circumference of the inner tube 60 at the end supports62, 64 under such conditions as to hermetically seal the moving switchparts under the most desirable conditions, such as in an atmosphere ofdry inert gas. If desired, insulating spacers or washers 72 may beslipped over the core extensions 14, 16 to bear against the outer endsof the end supports 62, 64 and the cylindrical tube 10. -As previouslymentioned, each of the individual switches such as the one justdescribed has its cylindrical tube 10 electrically insulated from othermetallic elements by means of the insulating strips 12. Also asmentioned, a potting compound is poured into the assembled switchassembly to provide additional insulation and hold the various switchesand component parts in their desired position.

When the coil 20 is deenergized and the individual switches are in theirnormal or released position, the switch elements have the position shownfor switch No. 3 in FIGURE 1. An electrically closed circuit is providedfrom the switching terminal on an L-shaped bracket 24 (labeled in FIGURE3) through the L-shaped bracket 24, the core extension 14, the firstcore element 40, the spring 48, the spring contact 50, the contact bar52, the support 68, the inner tube 60, the cylindrical tube 10, andfinally to the normally closed terminal (labeled in FIGURE 2) which isfastened to the cylindrical tube 10. An electrically open circuit alsoexists between the switching terminal and the normally open terminal onan L-shaped bracket 24 (labeled in FIG- URE 2) since the second coreelement 42 and its core extension 16 are electrically insulated from theremainder of the switch elements. When the relay coil 20 is energized,however, the armature 46 is drawn up in the air gap 44 towards the coreelements 40, 42 until the free end 56 of the spring 48 engages thecontact 58. The armature 46 continues to be drawn up into the air gap 44until the faces of the armature 46 contact the corresponding endsurfaces of the core elements 40, 42. This overtravel of the armature 46provides a desirable wiping of the free end 56 of the spring 48 acrossthe contact 58. An electrically closed circuit is thus provided from theswitching terminal on an L-shaped bracket 24 (labeled in FIG- URE 3)through the L-shaped bracket 24, the core extension 14, the first coreelement 40, the spring 48, the free end 56, the contact 58, the secondcore element 42, the core extension 16, and finally to the normally openterminal on an L-shaped bracket 24 (labeled in FIGURE 2). Anelectrically open circuit also exists between the switching terminal andthe normally closed terminal (labeled in FIGURE 2) which is fastened tothe cylindrical tube 10 because the spring contact 50 is disengaged fromthe contact bar 52. With the armature 46 of each individual switchcontacting the core elements 40, 42, a good magnetic path is providedbetween each of the core elements 40, 42 and the energizing coil 20.This path includes the asembly cover 26, the L-shaped brackets 24associated with the switching terminals, the core extensions 14, thefirst core elements 40, the armatures 46, the second core elements 42,the core extension 16, the L- shaped brackets 24 associated with thenormally open terminals, and finally back to the assembly cover 26.However, a gap of nonmagnetic material remains between the assemblycover 26 and each of the L-shaped brackets 24 as a result of theinsulating strip 28 on the interior surface of the assembly cover 26.This insures that each of the individual switches will drop out readilywhen the energizing coil 20 is deenergized.

FIGURE '4 shows an arrangement using three individual switches insteadof the six described above in connection with FIGURES 1, 2, and 3. InFIGURE 4, certain of the parts have the same reference numerals as theircorresponding parts in FIGURES l, 2, and 3. In the arrangement shown inFIGURE 4, the three switches are coextensively positioned in a triangle,and the coil, the coil form, and the assembly cover are shapedaccordingly. The view of FIGURE 4 shows the normally closed terminalsconnected to the cylindrical tube at the outer surface thereof toprovide good separation between these terminals. 'I hese normally closedterminals may be positioned elsewhere if desired. The arrangement shownin FIGURE 4 has a magnetic circuit similar to the one shown anddescribed in connection with FIG- URES l, 2, and 3.

While the invention has been described in two specific embodiments,namely a relay assembly having three individual switches and a relayassembly having six individual switches, it will be appreciated bypersons skilled in the art that different numbers of switches may beused in an assembly in accordance with the invention. For example, itwill be apparent to persons skilled in the ant that an assemblycomprising seven individual switches arranged with one central switchsurrounded by six switches provides a comp-act and efficientarrangement. And while the invention has been described with referenceto particular embodiments, it is to be understood that modifications maybe made by persons skilled in the art without departing from the spiritof the invention or from the scope of the claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. A relay assembly comprising a plurality of individual switches, eachof said individual switches comprising a core having first and secondcore elements of magnetic material, said core elements being separatedby a gap, a fiat elongated spring having one end fastened to said firstcore element and the other end positioned in the vicinity of butnormally separated from said second core element, said" springcomprising an armature of magnetic material positioned in the vicinityof said gap and normally spaced from said core elements, and a contactpositioned adjacent said spring, said spring being biased so that saidspring normally engages said contact, said individual switches beingpositioned together but electrically insulated from each other, anenergizing coil surrounding said individual switches, an assembly coverformed of magnetic material surrounding said energizing coil butelectrically insulated therefrom, and a bracket formed of a magneticmaterial fastened to each of said core elements for providing a magneticcircuit having a nonmagnetic gap between each of said individualswitches and said assembly cover.

2. A relay assembly comprising a plurality of individual switches, eachof said individual switches comprising within a non-magentic tube a corehaving first and second core elements of magnetic material, said coreelements being separated by a gap, a fiat elongated spring having oneend fastened to said first core element and the other end positioned inthe vicinity ofbut normally separated from said second core element,said spring comprising an armature of magnetic material positioned inthe vicinity of said gap and normally spaced from said core elements,and a contact positioned adjacent said spring, said spring being biasedso that said spring normally engages said contact, said individualswitches being positioned together but with said tubes being separatedfrom each other by insulation, an energizing coil surrounding saidpositionedtogether switches, an assembly cover formed of magneticmaterial and having an insulating strip on at least a portion of theinner surface thereof, and L-shaped brackets formed of a magneticmaterial fastened to each of said core elements for providing a magneticcircuit between each of said individual switches and said assemblycover, said mangeticcircuit including said insulating strip as a partthereof.

3. A relay assembly comprising a plurality of individual switches, eachof said individual switches comprising a core having first and secondcore elements of magnetic material, said core elements being separatedby a gap, an elongated spring having one end fastened to said first coreelement and the other end positioned in the vicinty of but normallyseparated from said second core element, an armature of magneticmaterial fastened to said spring, at least a portion of said armaturebeing positioned in said gap and spaced from said core elements, acontact bar positioned adjacent said spring, said spring being biased sothat said spring normally engages said contact bar, and a tube-likeelement formed of non-magnetic material positioned around said coreelements, said spring, said armature, and said contact bar whereby saidindividual switch provides a closed circuit between said first coreelement and said contact bar and an open circuit between said first coreelement and said second core element in response to an energizing coilbeing deenergized and whereby said spring is drawn toward said secondcore element to provide a closed circuit between said first core elementand said second core element and an open circuit between said first coreelement and said contact bar in repsonse to an energizing coil beingenergized, each of said individual switches being grouped together in acompact arrangement but having their respective tube-like elementselectrically insulated from one another by suitable insulating means, anenergizing coil positioned around said group of switches, an assemblycover formed of magnetic material and having electrical insulation on atleast a portion of its inner surface positioned around said energizingcoil, and an L-shaped bracket formed of magnetic material fastened toeach of said core elements with one of the surfaces of said L-shapedbracket being positioned against the inner surface of said insulation onsaid assembly cover, for providing support for said group of switchesand for providing a magnetic path between each of said individualswitches and said assembly cover, said magnetic path including saidinsulation on said assembly cover as a part thereof.

4. A relay assembly comprising a plurality of individual switches, eachof said individual switches comprising a core having first and secondcore elements of magnetic material, said core elements being separatedby a gap, an elongated spring having one end fastened to said first coreelement and the other end positioned in the vicinity of but normallyseparated from said second core element, an armature of magneticmaterial fastened to said spring, at least a portion of said armaturebeing positioned in said gap and spaced from said core elements, acontact bar positioned adjacent said spring, said spring being biased sothat said spring normally engages said contact bar, and a cylindricaltube formed of nonmagnetic material positioned around said coreelements, said spring, said armature, and said contact bar, saidcylindrical tube being electrically connected to said contact barwhereby said individual switch provides a closed electrical circuitbetween said first core element and said contact bar and an openelectrical circuit between said first core element and said second coreelement in response to an energizing coil being deenergized and wherebysaid spring is drawn toward said second core element to provide a closedelectrical circuit between said first core element and said second coreelement and an open electrical circuit between said first core elementand said contact bar in response to an energizing coil being energ-ized,each of said individual switches being coextensively grouped together ina compact arrangement but having their respective cylindrical tubeselectrically insulated from each other by suitable insulating means, anenergizing coi-l positioned around said grouped switches, an assemblycover that is formed of magnetic material and that has insulation on itsinner surface positioned around said energizing coil, and an L-shapedbracket formed of magnetic material fastened to each of said coreelements with a free flat surface of said L- shaped bracket beingpositioned against the inner surface of said assembly cover insulationfor prOViding support for said individual switches, each of saidindividual switches having a magnetic path including said L-shapedReferences Cited in the file of this patent UNITED STATES PATENTS2,037,535 Rankin Apr. 14, 1936 2,630,506 Buch Mar. 3, 1953 2,821,597Germanton et al. Jan. 28, 1958 2,889,424 Glore et al. June 2, 19592,892,052 Ducat-i June 23, 1959 2,902,558 Peek Sept. 1, 1959 2,938,982Brown et al. May 31, 1960

